These are old docs and we haven't found the time to completely move them.
You will find comprehensive new docs on
Since 2sxc 8.4 you can create content-blocks inside other content blocks. This allows you to create list/details scenarios and still use designed 2sxc-content block or even gallery apps inside the details-page.
I've written an extensive blog about this, please referr to that for now:
Inner Content Blocks allow Details-Page Design (new in 8.4) - like Modules inside Modules